Cog in the migration wheel: migratory waggle dances are necessary but not sufficient in the nest movement of the Asian giant honeybee Apis dorsata

Honeybees use waggle dances to inform nestmates about the locations of food and nest sites. The waggle duration corresponds to the distance to a resource, while its direction with respect to the vertical axis represents the resource direction in relation to the solar azimuth. Individual waggle runs within a dance often vary in duration and direction, and follower bees use the average spatial information for foraging. Honeybees also dance prior to nest movement, wherein waggle runs have directional similarity, but vary considerably in duration. The role of these dances, called migratory dances, has been elucidated mostly using artificially generated swarms which may not accurately represent long-term changes in the colony preceding migration. We explored temporal trends in waggle dances prior to migration from undisturbed colonies of the Asian giant honeybee, Apis dorsata. In two sites in India with either a year-round or seasonal presence of colonies, we asked whether dances are a sufficient predictor of migration. One site showed increased mean and error in the duration of dances in all colonies prior to migration. All study colonies migrated and the habitat was devoid of colonies in general. The second site was different in that all colonies had similar dance durations and error over time, although only one of the colonies migrated within the study period, while the others migrated months later. Thus, though migration is preceded by longer dances with greater error, these dances do not necessarily indicate imminent migration. Importantly, our findings suggest that the migratory response likely involves an interplay of several factors (e.g., resources, colony health) that are being constantly evaluated, and colonies may either migrate or revert to a resident state. These findings are the first observations of pre-migration dances from natural, undisturbed colonies (as opposed to artificial swarms) and are of significance as A. dorsata increasingly occupies urban areas and can potentially become invasive.